Second-generation antipsychotics (SGAs) are associated with significant comorbid metabolic abnormalities. Adjunct medications may be prescribed to treat these metabolic side effects, but the evidence supporting this practice (especially for the management of antipsychotic-associated dyslipidemia and hypertension) is limited. The purpose of this review was to evaluate the effects of adjunct medications on triglyceride, total cholesterol, low-density lipoprotein, high-density lipoprotein, and blood pressure levels in participants taking SGAs for psychosis. Studies were systematically searched and evaluated. Studies were included for review if participants were taking SGAs and if lipid and/or blood pressure levels were included as outcome measures. Statins, conventional lipid-lowering agents, fluvoxamine, ramelteon, topiramate, valsartan, telmisartan, omega-3 fatty acids, metformin (including both immediate-release and extended-release formulations), and a combination of metformin–sibutramine seemed to have beneficial effects on lipid levels. Valsartan, telmisartan, and topiramate appeared to be effective for controlling increases in blood pressure. The literature on adjunct medications for the treatment of antipsychotic-associated dyslipidemia and hypertension is not exhaustive, and long-term randomized-controlled trials would offer valuable results.